If you work at night and your eyes are tired by 10pm, the problem usually is not your monitor. It is the lamp sitting next to it.
Why a desk lamp fights your screen
A normal lamp throws light in every direction, including straight at the panel. That light bounces back into your eyes as a washed-out haze over whatever you are reading. You compensate by turning the screen brightness up, which is exactly the wrong move: now you have a bright screen in a dim room, the highest-contrast setup possible for eye strain.
What a monitor light bar does differently
It clamps to the top of the screen and uses asymmetrical optics: the light is physically shaped to fall forward onto the desk and not backward onto the glass. Same room brightness, zero reflection. That is the whole trick, and it is why a $40 light bar outperforms a $150 designer lamp for this one job.
The three specs that actually matter
Color temperature range. You want at least warm (around 3000K) and daylight (around 6500K). Warm at night so you are not fighting your own sleep, daylight during the day so colors read accurately.
CRI above 85. Color Rendering Index. Below 85, skin looks grey on camera and colors read wrong when you are editing. This is the spec cheap bars quietly leave out.
Stepless dimming. Three fixed brightness levels are never the level you want. Stepless means you land exactly right.
What it will not fix
A light bar will not fix a window behind your monitor, and it will not fix a ceiling light directly overhead. Deal with those first: a curtain and a lower-wattage bulb cost nothing.
Who should skip it
If you only use the desk in daylight with no direct sun on the screen, you do not need one. Buy a desk pad instead.
The short version
Desk lamp: lights the room, hits the screen, adds glare. Monitor light bar: lights the desk only, no glare, no desk space used. If you work after dark, the light bar is the upgrade. Ours ships free from a US warehouse in 5 to 7 business days.